This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1916 Excerpt: ...to the geological relations and the character of the mother rock. The mineral composition, the inclusion of the ore in a subsilicic rock, and the relatively unaltered condition of the ore and country rock, give this deposit the characteristics of a magmatic ore. It is possibly the unmetamorphosed equivalent of the ...
Read More
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1916 Excerpt: ...to the geological relations and the character of the mother rock. The mineral composition, the inclusion of the ore in a subsilicic rock, and the relatively unaltered condition of the ore and country rock, give this deposit the characteristics of a magmatic ore. It is possibly the unmetamorphosed equivalent of the lenses of pyrrhotite in "basic" layers of gneiss, and is an indication that certain of these puzzling occurrences are altered magmatic segregations. The Boulder batholith is well known to students of ore deposits because it was accompanied and followed by extensive mineralization, and especially because it encloses the enormous copper deposits at Butte. The Golden Curry mine at Elkhorn is in a region of intense mineralization,54 which occurred in and near the roof of the batholith. In this property there are two types of ore deposits: (1) a contact deposit between quartz monzonite and limestone, consisting of magnetite and some chalcopyrite accompanied by garnet; (2) the magmatic pyrrhotite deposit. The latter occurs 250 feet from the contact mentioned above, as the sulfid rich portion of a lens of fresh monoclinic pyroxene, pyrrhotite, and chalcopyrite. This is surrounded by a border zone, which grades into the normal quartz monzonite by the addition of, first, plagioclase, then hornblende, quartz, and the accessory minerals of the quartz monzonite, and finally biotite and orthoclase. According to 58 Knopf, A.--A magmatic sulphide ore-body at Elkhorn, Mont. Econ. Geol. 8, 323-336 (1913). e Knopf, A.--Ore deposits of the Helena mining region, Montana. Bull. 527, U. S. Geol. Surv. (1913) Knopf, the deposit is characterized by the absence of pneumatolytic or hydrothermal alteration products. In the vicinity, however, intense pneumatolytic ...
Read Less
Add this copy of A Study of the Magmatic Sulfid Ores to cart. $15.42, new condition, Sold by Ingram Customer Returns Center rated 5.0 out of 5 stars, ships from NV, USA, published 2022 by Legare Street Press.
Add this copy of A Study of the Magmatic Sulfid Ores to cart. $26.58, new condition, Sold by Ingram Customer Returns Center rated 5.0 out of 5 stars, ships from NV, USA, published 2022 by Legare Street Press.
Add this copy of A Study of the Magmatic Sulfid Ores to cart. $40.83, new condition, Sold by Revaluation Books rated 4.0 out of 5 stars, ships from Exeter, DEVON, UNITED KINGDOM, published 2008 by BiblioBazaar.
Add this copy of A Study of the Magmatic Sulfid Ores to cart. $53.20, new condition, Sold by Revaluation Books rated 4.0 out of 5 stars, ships from Exeter, DEVON, UNITED KINGDOM, published 2008 by BiblioBazaar.
Add this copy of A Study of the Magmatic Sulfid Ores to cart. $58.43, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2022 by Legare Street Press.
